void mainImage( out vec4 fragColor, in vec2 fragCoord ){
    vec2 uv = (fragCoord.xy / iResolution.xy);
    float offsetTop = 0.185;
    float offsetBottom = 0.155;
    float offsetLeft = 0.025;
    float offsetRight = 0.025;
    uv.y =(1.0-offsetTop-offsetBottom)*uv.y+offsetTop;
    uv.x =(1.0-offsetLeft-offsetRight)*uv.x+offsetLeft;
    vec4 color = texture(iChannel0, uv);
    fragColor = color;
}
